DTC P1569: Variable Tumble Control System (VTCS) Solenoid Valve, Circuit Malfunction: Condition

WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.

DTC is set when Powertrain Control Module (PCM) detects input voltage from VTCS solenoid valve is low (less than 3 volts). This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are:

VTCS solenoid valve malfunction.
Short or open circuit between VTCS solenoid valve and PCM.
Open circuit between main relay and VTCS solenoid valve.
PCM malfunction.